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Why I´m dissappointed in the preassembly  

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Rakku
(@rakku)
Trusted Member
Why I´m dissappointed in the preassembly

The MK3 is not my first prusa machine.

I had a MK2S which I built myself and that printer worked beautifully without any issues.

This time I was a bit greedy and didnt want to invest a full day (yeah, I need that long) into building the MK3 so I ordered one preassembled.
You pay around 250€ for the assembly (pretty hefty if you ask me, but okay).

So far I have around 200h of print time on the MK3, and have noticed many issues regarding the assembly.

1. First off, the y-axis pulley was completly loose and the belt was not tightened, I had to redo that.

2. The left z-leadscrew is ever so slightly bent.

3. The heatbed was rattling so bad when it moved, that I had to disassemble it and retighten the screws holding the bearings.

4. Before I could do that though, I had to work my way through 2 nearly completly stripped screws! Basicly the assembler stripped 2 screws of the heatbed.

5. And today I basicly lost a 12 h print because the wires of the extruder transistor were too squished and pulled, that the cables lost contact and it gave me a MINTEMP error midprint since the printer couldnt detect the temperature of the nozzle anymore.

To be honest, paying 250€ for this kind of sloppy work dissapoints me.
And no, I didnt contact support yet with these issues, because I notice new issues with the printer the more I print with it.
The loss of the 12h print yesterday made me write this thread out of frustration.

Its a great printer, really.
But the assembly was obviously rushed and I do think I still have to disassemble even the complete extruder because the z-axis is pretty hard to move by hand (the y-axis isnt after I tensioned/tightened everything correctly).

I had to get this off my chest, sorry for whining around, lol.

PS: I cant recommend getting the printer preassembled. Take the time and built it yourself, you´ll learn much more about the printer anyways.

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Posted : 05/02/2018 2:16 pm
Trae
 Trae
(@trae)
Active Member
Re: Why I´m dissappointed in the preassembly

I also got my printer preassembled, and was disappointed with the quality of the build.

LCD SD card reader busted, have to find the sweet spot for the SD card to be read.

The X axis belt would not stay tight, so I had to do some modifications to the X axis belt system.

Bad bearing on the Y axis.

Massive vibration from the PSU (ordered a complete replcement).

Bondtech gears have what appears to be rust already.

Reprinted the Z axis parts and the X axis idler/motor mount. The X axis idler is not aligned, which caused the belt wobble (not sure how they missed that).

I should have gotten a kit instead...

Posted : 05/02/2018 4:24 pm
gibsonlpsl
(@gibsonlpsl)
Eminent Member
Re: Why I´m dissappointed in the preassembly

This is exactly why I stayed with the kit version. I mean no disrespect, the assemblers obviously know how to do it well, but I think it comes down to the fact that they're never going to care about the quality of the build as much as you do. Plus the large amount of orders we're hearing about for the MK3 probably puts additional pressure on them to build faster.

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Posted : 05/02/2018 4:32 pm
Rakku
(@rakku)
Trusted Member
Topic starter answered:
Re: Why I´m dissappointed in the preassembly



Reprinted the Z axis parts and the X axis idler/motor mount. The X axis idler is not aligned, which caused the belt wobble (not sure how they missed that).

I should have gotten a kit instead...

Same here, a kit would have been better.

I have the same issue with the x axis belt, it wobbles heavily, but it does not really affect my print quality (at least I think?).

So how can I align everything?


This is exactly why I stayed with the kit version. I mean no disrespect, the assemblers obviously know how to do it well, but I think it comes down to the fact that they're never going to care about the quality of the build as much as you do. Plus the large amount of orders we're hearing about for the MK3 probably puts additional pressure on them to build faster.

Pressure to build faster cant be a excuse if the customer pays friggin 250€ for it to be honest.
If there is so much pressure on the people assembling the printers, then its the fault of the internal management, and I dont really care who is to blame.

Its just sad, that so many people have/had problems with their MK3 and everything around it.

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Posted : 05/02/2018 5:15 pm
Rakku
(@rakku)
Trusted Member
Topic starter answered:
Re: Why I´m dissappointed in the preassembly


This is exactly why I stayed with the kit version. I mean no disrespect, the assemblers obviously know how to do it well, but I think it comes down to the fact that they're never going to care about the quality of the build as much as you do. Plus the large amount of orders we're hearing about for the MK3 probably puts additional pressure on them to build faster.

Pressure to build faster cant be a excuse if the customer pays friggin 250€ for it to be honest.
If there is so much pressure on the people assembling the printers, then its the fault of the internal management, and I dont really care who is to blame.

Its just sad, that so many people have/had problems with their MK3 and everything around it.

...
Posted : 05/02/2018 5:17 pm
gibsonlpsl
(@gibsonlpsl)
Eminent Member
Re: Why I´m dissappointed in the preassembly


Pressure to build faster cant be a excuse if the customer pays friggin 250€ for it to be honest.
If there is so much pressure on the people assembling the printers, then its the fault of the internal management, and I dont really care who is to blame.

Its just sad, that so many people have/had problems with their MK3 and everything around it.

I'm not saying it should be an excuse, but it is a reason and it seems like you have the proof in hand, sadly. I'm disappointed with the numerous problems we've all had as well. The machine has great potential, but it needed a lot more work before release. I'm sure Prusa and the community will take it the rest of the way soon though. Hopefully your experience can provide some feedback to Prusa and help to anyone who is a potential buyer still considering.

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Posted : 05/02/2018 5:51 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: Why I´m dissappointed in the preassembly

I've noted the same thing (all the way back to the Mk2 actually); your examples are much more severe than mine though.

This sort of thing unfortunately flows from the top down.

It's kind of becoming clear that feedback from the assembly guys upwards is discouraged.

Instead of allowing their build guys to say, "Hey, these holes don't line up" so they can go back to the source files and say, "Hey, you're right, these holes really are wrong", they just crack the whip on their assemblers instead. Or "Hey, this part is printed badly." Or "Hey, yo, these rod and bearings are screwed" -- instead they just shrug and throw them into the machine.

Ultimately (and I know you guys are probably tired of me saying it) this is a design issue. PR has designed a machine that they themselves can't assemble properly. It's not the assembler's fault; it's the design.

For a converse example, notice in these Mk3 complaints the squareness of the frame is never a problem. That's because the design has been fixed so it's much harder to assemble incorrectly, unlike with the threaded rods. That's how you really fix the assembly issues. I could probably make a list of these kinds of things spanning back to the MK2.

It's the design.
It's the design.
It's the design.

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Posted : 05/02/2018 6:16 pm
rasmus.l
(@rasmus-l)
New Member
Re: Why I´m dissappointed in the preassembly

Yeah, I had an order in for an assembled version since early December, but I ended up canceling it based on all these reports of shoddy assembly work. I'll revisit in a couple of months to see if quality control has improved and perhaps re-order unless something else catches my eye in the meantime.

Posted : 05/02/2018 6:25 pm
martin.m25
(@martin-m25)
Estimable Member
Re: Why I´m dissappointed in the preassembly

I bought my MK2S assembled. After my first serious jam, I had to disassemble the extruder and one of the (deeply buried) screws was totally botched up, had to saw it apart (!). Lesson for my MK3 order:
1: buy the kit - the assembled version is likely messed up and I rather have my own mess than debug that of PR
2: buy the kit - sooner or later, the printer will fail and I'll have to take it apart anyway. Better know from the beginning how (dis-)assembly goes.
3: buy the kit - during assembly, I'll notice obvious design bugs (misaligned screw holes on the frame and such) and fix them while I build the printer.

A very good question though is if someone with no prior 3d printer experience should buy the kit or assembled version:
Answer A: Buy the kit. If you are not able to build it, you are not able to properly fix problems with the printer later anyway.
Answer B: Buy the assembled version, so you can at least (until the first printer failure) get some printing experience...

- Martin

- Martin...
Posted : 05/02/2018 6:30 pm
Rakku
(@rakku)
Trusted Member
Topic starter answered:
Re: Why I´m dissappointed in the preassembly

Well, I just found out that either the extruder thermistor cable has a fault ooor in the worst case the motherboard connector of the thermistor has a loose connection.

Either way, my printer cant print at the moment, since the extruder thermistor disconnects randomly when the extruder moves.

Pretty frustrated, took me over an hour to actually path the problem back to that cable/connector.

Done for today, going to shoot a video for the support and hope the support will actually do something.

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Posted : 05/02/2018 7:19 pm
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